Sweet, the 9x57 is a great medium bore round. It didn't have the "oomph" of the 9.3.62 or 375 H&H but it consistently put meat in the pot of a lot of African hunters.
If your rifle is an M98 action you could load to a performance level between the 358 Win (9x51) and 35 Whelen (9x63). In fact that is about where I would start looking at powder charges as they all use the same case head diameter and the real difference is taper, and shoulder angle, (51+63)/2=57.
THIS IS PURELY SPECULATION ON MY PART AND NOT TESTED LOAD DATA FOR THE 9x57. If you look at the data for IMR 4064 for 358 Win and 35 Whelen, the max charge is compressed for each load with a 200gr bullet. There is a ten grain difference in max load (49gr for 358 at 46.2k CUP, 59gr for 35 Whelen at 46.6k CUP), so I would expect that a max load for the 9x57 would just about split the difference and have a max load of 54 grains, compressed with a 200gr bullet and a starting charge of 49 grains. THIS IS PURELY SPECULATION ON MY PART AND NOT TESTED LOAD DATA FOR THE 9x57.
But the above process is how I would start figuring out my handloads for the 9x57, and always work up from the calculated starting charge. If however your rifle is not an M98 base rifle and instead is of the small ring variety, I would reduce the max charge to keep pressures under 45k CUP. I chose 4064 and a 200gr bullet because it is my standby powder and a 200gr bullet will cover all your hunting situations in North America (except possibly the great bears in Alaska).
Or you could just look in some older manuals that still list 9x57 load data.